From this Apple support document:

OLED technology delivers an incredibly high contrast ratio and high resolution. And with no backlight, OLED emits light through each pixel, allowing for a thinner display. The Super Retina display overcomes challenges with traditional OLED displays with its high brightness, wide color support, and has the best color accuracy in the industry.

If you look at an OLED display off-angle, you might notice slight shifts in color and hue. This is a characteristic of OLED and is normal behavior. With extended long-term use, OLED displays can also show slight visual changes. This is also expected behavior and can include “image persistence” or “burn-in,” where the display shows a faint remnant of an image even after a new image appears on the screen. This can occur in more extreme cases such as when the same high contrast image is continuously displayed for prolonged periods of time. We’ve engineered the Super Retina display to be the best in the industry in reducing the effects of OLED “burn-in.”

The post offers some best practices for the so-called Super Retina display (incredibly gorgeous, by the way). If there’s an iPhone X in your future, take a look.

[Via MacRumors]